Heinz Kerry arrived at the facility in critical condition, and remained that way early Sunday evening, although doctors had stabilized her, Brown said.

Brown said he could not immediately release any more details about the patient's condition or her illness.

Nantucket Police Lt. Jerry Adams said a call requesting medical aid was received just after 3:30 p.m. for a home on Hulbert Avenue, and an ambulance was dispatched. Online records show the property is connected to Heinz Kerry's family.

Heinz Kerry is the widow of former U.S. Senator John Heinz, heir to the Heinz ketchup fortune. She married John Kerry in 1995.

John Kerry has been at the Nantucket home since returning from a nearly two-week around-the-world diplomatic trip to the Mideast and Southeast Asia in the pre-dawn hours of July 3.

Before his wife's medical problem, he had planned to return to Washington on Monday and then co-host with Treasury Secretary Jack Lew high-level strategic and economic talks with senior Chinese officials on Wednesday and Thursday.

Kerry had also spoken of his desire to make his sixth trip to Israel as secretary starting at the end of the week. State Department officials said Kerry's schedule may now change pending developments with his wife's health.